Localized Lateral Thermal Buckling of Pipelines With a Circular Layout

2016 ◽  
Vol 138 (6) ◽  
Author(s):  
Jianbei Zhu ◽  
Mario M. Attard
Keyword(s):  
Thermal Loading ◽  
Thermal Stresses ◽  
Finite Strain ◽  
Constitutive Relations ◽  
Lateral Expansion ◽  
Lateral Buckling ◽  
Included Angle ◽  
Buckling Behavior ◽  
Parametric Studies ◽  
Numerical Strategy

A numerical strategy is developed and used to investigate the localized lateral buckling of circular pipelines under thermal loading and friction. The constitutive relations for circular pipelines are derived for thermal stresses and finite strain based on a hyperelastic constitutive model. The prebuckling lateral expansion and localized postbuckling deformation are investigated. A critical included angle for circular profiles is studied. Beyond the critical included angle, increasing the included angle of the pipeline or changing the boundary conditions does not influence the localized buckling behavior. Parametric studies are performed and the results are validated with ansys.

Lateral buckling behavior and strengthening techniques of coped steel I-beams

2015 ◽  
Vol 108 ◽  
pp. 11-22 ◽  
Author(s):  
Sherif A. Ibrahim ◽  
Abdelrahim K. Dessouki ◽  
Seham A. El -Sa'eed
Keyword(s):  
Lateral Buckling ◽  
Buckling Behavior

scholarly journals Experimental and numerical investigation of the transition zone of locally steel-reinforced joining areas under combined tension–bending loading

2019 ◽  
Vol 54 (17) ◽  
pp. 2339-2352 ◽  
Author(s):  
E Petersen ◽  
J Koord ◽  
O Völkerink ◽  
D Stefaniak ◽  
C Hühne
Keyword(s):  
Carbon Fibre ◽  
Transition Zone ◽  
Thermal Stresses ◽  
Cohesive Zone Model ◽  
Zone Model ◽  
Lightweight Structures ◽  
Reinforced Plastics ◽  
Hybrid Region ◽  
Parametric Studies ◽  
Carbon Fibre Reinforced Plastics

In modern lightweight structures, the use of fasteners is preferred to other joining techniques. An approach to increase the bearing strength is the local metal hybridisation, where carbon fibre-reinforced plastics layers are substituted locally by metal foils of the same thickness. The local replacement leads to a transition zone between the hybrid region and the pure carbon fibre-reinforced plastics region. The present work deals with the investigation of different transition zone patterns of carbon fibre-reinforced plastics-steel hybrid specimens in combined tension–bending tests and accompanying non-linear static simulation. The simulation includes delamination and intralaminar damage with the use of a cohesive zone model and Cuntze’s failure mode concept. Furthermore, residual thermal stresses are considered. A satisfying agreement of test and simulation is achieved, which allows the identification of beneficial transition zone configurations and also validates the numerical model for further parametric studies.

Weldment Analysis of a Diesel Engine Exhaust Manifold

2016 ◽  
Author(s):  
Masoud Mojtahed ◽  
Nganh Le ◽  
Jerry Wayne DeSoto
Keyword(s):  
Diesel Engine ◽  
Thermal Loading ◽  
Thermal Stresses ◽  
Engine Performance ◽  
Exhaust Manifold ◽  
Element Analysis ◽  
Performance Requirements ◽  
Pipe Model ◽  
Key Factor ◽  
Double Pipe

The Exhaust Manifold is an increasingly important component of industrial turbocharged diesel engines. It can be a key factor to increase the efficiency of any engine, in this case a power plant diesel engine. Analysis of the various structural and thermal loading of the liquid-cooled manifolds is of vital importance to increase the components efficiency and overall engine performance. In this analysis, problems such as thermal stress issues causing manifold failure are identified and redesigned to meet performance requirements and environmental regulations. These manifolds are of complicated shapes and contain many weld joints to attach several integral parts. The weld regions are identified to be sensitive to thermal stresses and most likely prone to failure. The welds were added to the model in ANSYS® Workbench. Computational Fluid Dynamics (Fluent) and Finite Element Analysis (FEA) were used to analyze the welded model. The main outcome was to understand the welds behavior using the ANSYS software and its powerful tools and to determine whether the areas containing welds are likely to fail under the given conditions. A simple double pipe model was also created and congruently analyzed to validate the results and the techniques used in analyzing the manifold model.

Post-Buckling Analysis of FGM Beam Subjected to Non-Conservative Forces and In-Plane Thermal Loading

2012 ◽  
Vol 152-154 ◽  
pp. 474-479
Author(s):  
Feng Qun Zhao ◽  
Zhong Min Wang ◽  
Rui Ping Zhang
Keyword(s):  
Shooting Method ◽  
Thermal Loading ◽  
Governing Equations ◽  
Temperature Dependent ◽  
Tangential Load ◽  
Simply Supported ◽  
Runge Kutta Method ◽  
Buckling Behavior ◽  
Post Buckling ◽  
Fgm Beam

Based on the Kirchhoff large deformation theory, the post-buckling behavior of right movable simply supported FGM beam subjected to non-conservative forces and in-plane thermal loading was analyzed in this paper. The temperature-dependent and spatially dependent material properties of the FGM beam were assumed to vary through the thickness. The nonlinear governing equations of FGM beam subjected to a uniform distributed tangential load along the central axis and in-plane thermal loading were derived. Then, a shooting method and Runge-kutta method are employed to numerically solve the resulting equations. The post-buckling equilibrium paths of the FGM beam with different parameters were plotted, and the effects of non-conservative force, temperature, gradient index of FGM on the post-buckling behavior of right movable simply supported FGM beams were analyzed.

Analysis of a Bow-Free Prestressed Test Specimen

2014 ◽  
Vol 81 (11) ◽  
Author(s):  
E. Suhir ◽  
J. Nicolics
Keyword(s):  
Cross Sections ◽  
Test Specimen ◽  
Thermal Loading ◽  
Thermal Stresses ◽  
Effective Means ◽  
Physical Nature ◽  
Accelerated Testing ◽  
Mode Shift ◽  
Temperature Range ◽  
Operation Conditions

Broadening the temperature range in accelerated testing of electronic products is a typical measure to assure that the product of interest is sufficiently robust. At the same time, a too broad temperature range can lead to the shift in the modes and mechanisms of failure, i.e., result in failures that will not occur in actual operation conditions. Application of mechanical prestressing of the test specimen could be an effective means for narrowing the temperature range during accelerated testing and thereby achieving trustworthy and failure-mode-shift-free accelerated test information. Accordingly, simple engineering predictive models are developed for the evaluation of the magnitude and the distribution of thermal and mechanical stresses in a prestressed bow-free test specimen. A design, in which an electronic or a photonic package is bonded between two identical substrates, is considered. Such a design is often employed in some today's packaging systems, in which the “inner,” functional, component containing active and/or passive devices and interconnects is placed between two identical “outer” components (substrates). The addressed stresses include normal stresses acting in the component cross sections and the interfacial shearing and peeling stresses. Although the specimen as a whole remains bow-free, the peeling stresses might be nevertheless appreciable, since the outer components, if thin enough, deflect to a greater or lesser extent with respect to the inner component. The numerical example has indicated that the maxima of the interfacial thermal shearing and peeling stresses are indeed comparable and that these maxima are on the same order of magnitude as the normal thermal stresses acting in the components' cross sections. It is shown that since the thermal and the prestressing mechanical loads are of different physical nature, the stresses caused by these two load categories are distributed differently over the specimen's length. It is shown also that although it is possible and even advisable to apply mechanical prestressing for a lower temperature range, it is impossible to reproduce the same stress distribution as in the case of thermal loading. The obtained results enable one to shed light on the physics of the state of stress in prestressed bow-free test specimens in electronics and photonics engineering.

IN-PLANE NONLINEAR BEHAVIOUR OF CIRCULAR PINNED ARCHES WITH ELASTIC RESTRAINTS UNDER THERMAL LOADING

2006 ◽  
Vol 06 (02) ◽  
pp. 163-177 ◽  
Author(s):  
M. A. BRADFORD
Keyword(s):  
Closed Form ◽  
Thermal Loading ◽  
Virtual Work ◽  
Thermal Buckling ◽  
Nonlinear Behaviour ◽  
Principle Of Virtual Work ◽  
Equilibrium Equations ◽  
Structural Behaviour ◽  
Geometric Imperfection ◽  
Included Angle

This paper considers the nonlinear in-plane behaviour of a circular arch subjected to thermal loading only. The arch is pinned at its ends, with the pins being on roller supports attached to longitudinal elastic springs that model an elastic foundation, or the restraint provided by adjacent members in a structural assemblage. By using a nonlinear formulation of the strain-displacement relationship, the principle of virtual work is used to produce the differential equations of in-plane equilibrium, as well as the statical boundary conditions that govern the structural behaviour under thermal loading. These equations are solved to produce the equilibrium equations in closed form. The possibility of thermal buckling of the arch is addressed by considering an adjacent buckled equilibrium configuration, and the differential equilibrium equations for this buckled state are also derived from the principle of virtual work. It is shown that unless the arch is flat, in which case it replicates a straight column, thermal buckling of the arch in the plane of its curvature cannot occur, and the arch deflects transversely without bound in the elastic range as the temperature increases. The nonlinear behaviour of a flat arch (with a small included angle) is similar to that of a column with a small initial geometric imperfection under axial loading, while the nonlinearity and magnitude of the deflections decrease with an increase of the included angle at a given temperature. By using the closed form solutions for the problem, the influence of the stiffness of the elastic spring supports is considered, as is the attainment of temperature-dependent first yielding of a steel arch.

Thermal stresses in a rotating, nonhomogeneous, anisotropic disk of varying thickness and density

1975 ◽  
Vol 10 (3) ◽  
pp. 137-142 ◽  
Author(s):  
G V Gurushankar
Keyword(s):  
Thermal Loading ◽  
Thermal Stresses ◽  
Closed Form Solution ◽  
Rotating Disk ◽  
Form Solution ◽  
Annular Disk ◽  
Varying Thickness ◽  
Principal Axes ◽  
Rotationally Symmetric ◽  
Anisotropic Disk

Closed form solution is obtained for stresses in a rotationally symmetric, nonhomogeneous, anisotropic, annular disk of varying thickness and density, subjected to thermal loading. Analysis is presented for a particular type of anisotropy, namely Polar Orthotropy, in which axes of anisotropy coincide with the principal axes of stresses at each point in the disk. The variations of homogenity, density and thickness are assumed to be hyperbolic. Numerical results in the form of graphs presented show the effect of nonhomogenity, density and degree of orthotropy on the stress distribution in a disk subjected to constant and varying temperature gradients. Homogeneous, varying density anisotropic rotating disk of varying thickness forms a special case of the analysis.

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